Ejector assembly with lockable storeengaging presser foot



March 11, 1969 c. A. DAMM 3,431,824

EJECTOR ASSEMBLY WITH LOCKABLE STORE-ENGAGING PRESSER FOOT Filed July 31, 1967 Sheet of 2 INVENTOR.

CARL A. DAM M AT TORN EY March 11, 1969 c. A. DAMM 3,431,824

EJECTOR ASSEMBLY WITH LOCKABLE STORE-ENGAGING PRESSER FOOT Filed July 31, 1967 Sheet 2 of 2 INVENTOR.

CARL A. DAMN BY l m ATTORNEY United States Patent Chico 3,431,824 Patented Mar. 11, 1969 3,431,824 EJECTOR ASSEMBLY WITH LOCKABLE STORE- ENGAGING PRESSER FOOT Carl A. Damm, Upper Black Eddy, Pa., assignor to the United States of America as represented by the Secretary of the Navy Filed July 31, 1967, Ser. No. 657,738 US. Cl. 92132 10 Claims Int. Cl. F01!) 31/00, 9/00; F41f /02 ABSTRACT OF THE DISCLOSURE A pyrotechnically actuatable ejector device for separating stores from store releasing racks including an integrally cast casing having pyrotechnic cartridge receiving chainbers and a telescoping piston receiving chamber interconnected by a combustion chamber and including a piston carried, spring retracted, presser foot assembly which is adjustable for positioning adjacent a store suspended from the rack. A spring element is connected to a relatively nonrotatable portion of the presser foot assembly, extends through a threadably received presser foot and is urged by spring force into a radial groove formed in the store adjacent surface of the presser foot to prevent further rotation of the presser foot.

Background of invention Ejector assemblies are conventionally used with an aircraft bomb rack for efiecting a separation of a store from the rack upon releasement of the store. Unless the presser foot of the ejector assembly is positioned in close adjacency to or in engagement with the releasably suspended store, the store may be dented or otherwise damaged by the presser foot upon actuation of the ejector. Known structures for positioning the presser foot adjacent the store frequently are unable to function properly because of the vibration to which the store, the rack and the ejector assembly are subjected during flight. Addi; tionally, adjustment of the presser foot for variously configured stores may change the compression ratio of known pyrotechnic ejector assemblies.

Summary of invention It is the general purpose of this invention to provide an improved ejector assembly having a presser foot which can be locked in a position closely adjacent a releasably suspended store in spite of vibration to which it may be subjected. Briefly, the purpose may be accomplished by providing an adjustable presser foot assembly which is carried by the extendable end of an ejector piston and which includes a spring element having one end fixed relative to the piston and the other end extending through the assembly and normally urged into locking engagement with a relatively adjustable portion of the presser foot assembly.

Brief description of drawing FIG. 1 represents a cross-sectional view in elevation of an improved ejector assembly including an adjustable, lockable presser foot assembly;

FIG. 2 represents a cross-sectional view in elevation of the presser foot assembly taken generally along line 22 of FIG. 1, portions of the ejector assembly being omitted;

FIG. 3 represents an inverted plan view of the storeadjacent surface of the presser foot assembly of FIG. 2; and

FIG. 4 represents an isometric view of a spring element performed for incorporation into the presser foot assembly of FIG. 2.

Description of preferred embodiment As shown in FIG. 1, the vertically arranged ejector assembly, generally designated as 10, is removably secured to a bomb rack 11 such as of the type described in US. Patent No. 3,036,852 for a Stores Rack issued May 29, 1962, to C. W. Mullison. The ejector 10 includes a bifurcated casing 12 having a body portion 13 from which a belled, dual chambered breech 14 and a cylindrical piston sleeve 15 extend downward toward a store 16 which has been releasably secured to the rack 11 by means not shown herein. The breech 14 includes a parallel pair of cylindrical chambers 14a and 14b which are'formed there in to receive pyrotechnic cartridges such as17 and which extend therethrough into the body portion 13 from respective threaded, larger diametered, cylindrical recesses such as 14c. The threaded recesses such as are each adapted for receiving an ignition cap such as 18 which functions to fire the cartridge 17 for generating explosive gases in response to an electrical command signal applied thereto through a lead 19. The sleeve 15 has formed therein a cylindrical piston chamber 15a which extends therethrough into the body portion 13 and is of a size to receive a piston 20 of the type having an inner, further extendable, telescoped piston member 21. The body portion 13 includes formed therein a combustion chamber 13a which connects the cartridge chambers 14a and 14b with the piston chamber 15a. The body portion 13 also includes an internal ramp 1312 which protrudes into the chamber 13:: intermediate its junctions with the piston chamber 15a and the adjacent cartridge chamber 13a and which inclines upwardly therefrom both toward the piston chamber 15a and toward the longitudinal side of the chamber 14a. The ramp 13b functions to cause a cyclone-like flow of the explosive gases adjacent the inner terminus of the piston chamber 15a which gases emanate from the cartridge chambers 14a and 14b and spiral downward to actuate the telescoped piston 20. The sleeve 15 also includes a parallel pair of externally projecting helical threads 22 which extend peripherally there about adjacent the junction of the sleeve 15 with the body portion 13. As shown in the above-indicated patent to Mullison, the body portion 13 of the casing 12 may include poppet valves, not shown, and an actuating piston, not shown, for causing the rack 11 to release the store 16.

While other materials are suitable, the casing 12 conveniently and inexpensively may be investment cast from maraging steel and thereafter subjected to pressure tests using a suitably configured pressure jig adapted for connection to the sleeve 15, as by connection to the threads 22, and to the belled breech 14, as by connection to an aperture 14d extending through the breech 14 transversely of and between the cartridge chambers 14a and 14b. Thereafter, the casing 12 may be age hardened by subjection for two or three hours to a temperature of about 900 F.

The helical threads 22 projecting from the sleeve 15 have a sufiicient length for receiving one and a half turns of one end of a coil spring 30 which is coaxially received about the sleeve 15 and which has a notch formed in each of its ends. A spring-loaded locking-pin 31 is slidingly received by the upper spring notch through adjacent, aligned apertures extending through the threads 22 for securing the spring 30 to the sleeve 15. The pin 31 is withdrawable into an aligned bore 13c formed in the body portion 13 when a bore obstructing, removable pin 32, which normally secures the assembly 10 to the rack 11, has been withdrawn from its locking position. A tubular piston stop member 33 of brass is threaded into the open end of the sleeve 15, and its upper end, which projects inwardly of the sleeve, functions to limit the outward excursion of the piston 20 under pressure. The inwardly beveled lower end of the stop member 33 functions to buffer the spring driven inward excursion of a lockable presser foot assembly, generally designated as 40, which is carried by the telescoped piston member 21 and is connected to the lower end of the coil spring 30.

More particularly, the presser foot assembly 40 includes a threaded, cylindrical connecting member 41 having a coaxial boss portion 42 which extends upwardly therefrom and is received within a coaxial recess 21a formed in the extendable end of the telescoped piston member 21. A weight reducing, cylindrical recess 42a extends coaxially into the boss portion 42. The connecting member 41 includes an annular recess 41a coaxially disposed about the boss 42 which defies surfaces for abutting engagement of the member 41 with the end of the telescoped piston member 21 and with the beveled stop 33 and radially terminates in a helical thread 43 adapted for receiving one and a half turns of the lower end of the coil spring 30. The spring 30 is secured under tension to the member 41 by a countersunk set screw 44 which extends across the lower spring notch. As shown in FIG. 2, the store facing surface of the member 41 also includes an annular recess 41b which defines a coaxial protuberance 45 having a wrench receiving socket 45a formed therein. Two pairs of coplanar, upwardly extending, converging bores, such as the pair of bores 41c and 41d which extend from the recess 41b to the recess 42a, are formed in the member 41 on opposite sides of the protuberance 45. The member 41 also may be investment cast in maraging steel.

A tubular presser foot 46 is internally threaded for an adjustable connection to the longitudinal periphery of the member 41 and includes at its store adjacent end an inwardly extending annular flange 47 which defines a circular aperture 47a and which is movable from a withdrawn position abutting the member 41 to a fully extended position by rotating or unscrewing the tube 45. Since the coil spring 30 tends to clamp the member 41 to the stop member 33 and prevent rotation of the member 41 relative to the sleeve 15, the foot 46 may be adjusted to a withdrawn position to prevent obstructing the loading of a store 16 unto the rack 11 and then may be unscrewed to the desired position of close adjacency to or engagement with the store 16, the compression ratio of the assembly being the same for stores of various Sizes or configurations since the piston 20 is not moved thereby from its withdrawn position. The store adjacent surface of the flange 47 of the foot 46 includes six symmetrically positioned, radially extending grooves 47b, as shown in FIG. 3.

In order to prevent relative rotation of the foot 46 from its adjusted position adjacent the store 16, a preformed, bifurcated spring element 48 has each of its side members threaded through a respective one of the pairs of the bores, such as 41c and 41d in the member 41, the free ends of the sides extending through the aperture 47a in the foot 46 and being confined together within an oval tube 47 which is crimped as at 50. The tube 49 is normally urged by spring action of the element 48 to engage the flange 47 and be received by grooves 47b and rojects outwardly of the foot 46 in a plane normal to the longitudinal axis, not shown, of the store 16.

More particularly, referring to FIG. 4, before incorporation into the assembly 40, the thrice bent arallel sides of the preformed spring element 48 normally lie in respective parallel planes and extend from an intermediate connecting portion 48a having a curvature for substantially conforming to the periphery of the protuberance 45 between the openings of the bores such as 410. The portions of the sides of the element 48 extending from the intermediate portion 48a to a first acute bend at A are long enough to be threaded through respective first bores in a pair such as 410 through the recess 42a and through respective second bores, such as 41d, in the pairs, the bend at A being positionable adjacent the recess 41b. The second preformed bends at B in each of the sides of the element 48 are of a size and are spaced from the bends at A a sufficient distance to assure that the free ends of the element 48 extending from the bends at B when confined together will urge the tube 49 into one of the grooves 47b in the flange 47 whether the tubular presser foot 46 has been fully extended or fully withdrawn, The free ends of the sides of the element 48 terminate in third bends at C which have a curvature substantially conforming to that defined by the pairs of converging bores such as 41c and 41d to assure that the element 48 may be readily threaded through the member 41, the bends at C being clipped off after the element 48 has been threaded.

The oval tube 49 is long enough to extend substantially to the bends at B and draws the free ends of the sides of the element 48 together to form a converging configuration of the side portions which extend from the bores such as 41d and through the bends at A and B and to the inner end of the tube 49. Since relative movement of the free ends of the sides of the element 48 is prevented by the crimp at 50 of the tube 49, the converging configuration of the element 48 tends to limit the tube to movement in a plane normal to the longitudinal axis of the store 16. Consequently, locking of the presser foot 46 in a selected orientation is further assured.

In using the lockable presser foot assembly 40, the free end of the tube 49 is pressed downwardly causing a portion of the spring element 48 to engage the adjacent periphery of the store 16. Thereupon the tubular presser foot 46 may be unscrewed toward engagement with the store 16 until further rotation thereof is prevented by reason of entrapment of the tube 49 between the store 16 and the foot 46 adjacent one of the grooves 47b in the annular flange 47. The foot 46 is then so positioned that, when the end of the tube 49 is released, the spring action of the element 48 causes the tube 49 to move upwardly to align itself within the groove 47b. The element 48 thereby prevents further rotation of the presser foot 46 even though it may be subjected to severe vibration. In using the ejector assembly 10 with stores of relatively small diameter, the tubular foot 46 may easily be unscrewed far enough to engage a longitudinal portion of the store periphery since the tube 49 projects outwardly of the foot 46 in a plane normal to the store axis and since the spring adjacent portion of the flange 47 will be spaced from the store 16.

It should be understood, of course, that the foregoing disclosure relates only to a preferred embodiment of the invention and that numerous modifications or alterations may be made without departing from the spirit and scope of the invention.

What is claimed is:

1. Apparatus comprising:

a piston sleeve adapted for connection to a rack;

a piston slidably received within said sleeve and movable under pressure toward one end of said sleeve;

a presser foot assembly connected to said piston, said assembly including a. connecting member connected to said piston and a relatively movable presser foot which is threadably connected to said connecting member and is adjustably positionable closely adjacent a store; and

a spring element having one portion connected to said connecting member of said presser foot assembly and having another portion thereof movable under spring action to lockingly engage means on said relatively movable presser foot to positively maintain the angular and axial positioning of said relatively movable foot.

2. Apparatus according to claim 1 wherein:

said. means on said relatively movable presser foot is a groove formed therein for receiving said other portion of said spring element.

3. Apparatus according to claim 2 further including:

a coil spring coaxially arranged about said sleeve and having its ends connected respectively to said sleeve and to said connecting member normally urging said connecting member into engagement with said one end of said sleeve.

4. Apparatus according to claim 2 wherein:

a free end of said other portion of said spring element protrudes outwardly of said relatively movable presser foot, said other portion being movable from engagement with said foot in a plane normal to a longitudinal axis of a store carried by a rack.

5. Apparatus according to claim 2 wherein said relatively movable presser foot includes:

a tube having one end threadably connected to said connecting member and having an annular flange which extends inwardly from the other end of said tube and defines a coaxial aperture through which said spring element extends from said connecting member, said groove radially extending across surface of said flange positionable adjacent a store.

6. Apparatus according to claim 5 wherein:

said spring element includes a pair of side portions which divergingly extend from said other portion of said element and are connected in spaced relation to said connecting member.

7. Apparatus according to claim 6 wherein:

said connecting member has formed therein in spaced relation first and second passageways extending therethrough; and

said spring element includes an intermediate portion from which said side portions extend through a respective one of said first and second passageway to said other portion of said element.

8. Apparatus according to claim 7 wherein:

said side portions include extended ends forming said other portion of said element; and

said apparatus further includes an elongated tiTbular member within which are juxtaposed said extended ends of said side portions in fixed relation to each other.

9. Apparatus according to claim 8 wherein:

a store adjacent surface of said connecting member includes a recess, both ends of each of said first and second passageways communicating therewith; and

said side portions of said spring element each have preformed therein first and second spaced apart bends, said first bends being positioned adjacent the egress of said side portions from said connecting member and said second bends being positioned adjacent the innermost end of said elongated tubular member.

10. Apparatus according to claim 9 wherein:

said apparatus further includes a tensioned coil spring coaxially arranged about said sleeve and having one end connected to said connecting member, the other end of said coil having a notch formed in the periphery thereof;

said sleeve includes spaced from said one end thereof an external helical thread for receiving said other end of said coil spring, said thread having a transverse aperture formed therein, said notch registering with said transverse aperture; and

said apparatus further includes a spring loaded pin removably positioned to extend through said aperture and across said notch.

References Cited UNITED STATES PATENTS 1,229,808 6/1917 Stump 15113 2,044,699 6/1936 Johnson 92-1 14 3,036,852 5/1962 Mullison 294-83 3,266,834 8/ 1966 Lebovitz 89-1.5 X

MARTIN P. SCHWADRON, Primary Examiner.

I. C. COHEN, Assistant Examiner.

US. Cl. X.R. 

